Bloodstream Infections caused by Klebsiella pneumoniae and Serratia marcescens isolates co-harboring NDM-1 and KPC-2.

Abstract

Carbapenem-resistant Enterobacteriaceae is a worldwide health problem, however isolates carrying both blaKPC-2 and blaNDM-1 are unusual. Here we describe microbiological and clinical characteristics of five cases of bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae and Serratia marcescens co-harboring blaKPC-2 and blaNDM-1.Of the five blood culture isolates, three from are from hematopoietic stem cell transplantation patients, one from a renal transplant patient, and one from a soft tissue surgical patient. All patients lived in low-income neighborhoods and had no travel history. Despite antibiotic treatment, four of five patients died. The phenotypic assays showed that Meropenem added with either EDTA, PA or both showed increased zone of inhibition in comparison to Meropenem alone. Molecular tests confirmed blaKPC-2 and blaNDM-1 genes, the K. pneumoniae were assigned as ST258 and ST340 by Whole Genome Sequencing.This case-series showed high mortality of BSI caused by Enterobacteria coproducing KPC-2 and NDM-1. The detection of samples co-harboring blaKPC-2 and blaNDM-1 remains unsatisfactory with phenotypic assay. Routine microbiology laboratories must be on alert for samples co-harboring these mechanisms.